1. Field of the Invention
The present invention relates to personal computer (PC) cards, particularly to the power management of PC cards.
2. State of the Art
PC cards are a common way to add peripheral devices to a personal computer. Elements such as memory or communication devices, can be placed on a PC card having a standard interface with personal computers. A common interface standard for PC cards is the Personal Computer Memory Card Interface Association (PCMCIA) standard. The PC cards are typically powered by the personal computer to which they are attached. This causes no problems when the PC cards are used with desktop computers connected to a wall power outlet. This can cause problems, however, when the PC cards are used with portable computers, especially handheld personal computers. For example, some handheld personal computers are powered by two AA batteries, and thus there is little spare current for power-using elements on the PC card. This can effectively limit the types of PC cards used with handheld computers.
It is desired to have an improved method and apparatus for managing the power supplied to the PC card.